About two weeks ago I posted an article that I snipped from mods.dk about the 706mkIIg finals being obsolete. I did some investigating and determined that the Icom is replacing the SRFJ7044power FET with the RD70HVF, the same power FET that'sused in the Icom IC-2720 dual band. If you check theproduct reviews in eHam.net under;

Transceivers: VHF/UHF Base/Mobile (non hand-held)/ICOM IC-2720H

You will see several complaints about finals burningout in the IC-2720.

I hope that Icom isn't using the same finals in theIC706MKIIG that are causing problems in 2720!!

Here a repeat of the article.---------Snip--------

The 706MKIIG radio has 2 different versions of the PA board. The older PA board's finals (1590002690)aka (srfj7044) are no longer available and would require replacement of the PA board. The newer style PA board transistors are part# 1560001190 (rd70HVF) and can be ordered by The 2 styles of transistors are not interchangeable.

The complete PA board is part# 98413600 and sells for apx $442. The catch 22 is that this board is the old style board, with the old transistors. We do not have the new style boards available yet so, if the finals fail again, it's another board replacement.

775(DSP)/706MKIIG FinalsThese two, probably others, and any manuf. who used the J7004 MosFet for a final, have a terminal issue. The finals (SR(F or K)J7004(MP) are no longer available. I have tried to contact a few sources, and a couple of parts hunters.. no Stock, No availability. Supposedly ICOM has a way to use MRF140's to replace them. This is unconfirmed at this time, I will update this later if I can find out how, and if it is true. The PA in the MKIIG was changed about 2 years ago to a newer (totally different) device. Supposedly you can swap out PA units for about $800! hardly worth it. The 775(DSP) has had very few cases of Final failure, the 706 MKIIG has had more cases of it. Beware buying used MKIIG's, I have been unable so far to get a serial number cut off on the older MKIIG's. The newer final for the MKIIG I believe is the MRF 140MP. "UPDATE" the new final is the MRF140, and there is "unconfirmed" info that the MRF140 is a replacement for the J7004. The spec sheets say this can't be. The reactance and impeadence is quite a bit different between the two devices. At ICOM's price of $280 a pair, I won't be jumping in there to try and see what happens. As I find out more I will update this

The MRF 104's will probably replace the outputsin the HF section but I don't think they willwork in the VHF/UHF side.

I don't it's fair to blame Icom for changes in thedesign.

It's motorola that discontinued the part and createdthe shortage. And while were on the subject, Semiconductor surplus dealers are cut throat scumbags that buy up all of the excess stock and inflatethe price so high that the part cost more the theoriginal equipment.

Copyright 2000-2017 eHam.net, LLC
eHam.net is a community web site for amateur (ham) radio operators around the world.
Contact the site with comments or questions.
WEBMASTER@EHAM.NETSite Privacy Statement